Worldwide solid waste production is increasing at an alarming rate. Solid waste ranges in size, shape and material. Non-limiting examples of high volume solid wastes include:    1. household garbage and trash (Municipal Solid Waste),    2. drill cuttings produced during the drilling of an oil or gas well    3. wastewater treatment plant sludge    4. medical waste    5. unburned carbon on flyash and coal fines    6. red mud which is the remaining bauxite waste from alumina production    7. obsolete computers and electronic equipment (Waste Electrical and Electronic    5 Equipment)    8. saw dust and wood chips    9. bagasse from sugar mills    10. rice straw    11. animal manure    12. radioactive hazardous wastes produced from manufacturing nuclear material for nuclear power plants and nuclear weapons.
Worldwide gaseous waste emissions are also increasing at an alarming rate. Worldwide natural gas production in 1998 exceeded 101,891 billion cubic feet (bcf). However, over 3.7% or 3,724 bcf of the produced gas was flared or vented worldwide. The vented or flared gas is a wasted and untapped source of energy. The U.S.'s Greenhouse Gas (GHG) releases for the flared natural gas flared in 1998 was about 3.9 million metric tons of carbon equivalents (MMTCE).
Also, total U.S. greenhouse gas emissions rose in 1998 to 1,834.6 MMTCE, which is 11.2 percent above the 1990 baseline of 1,649.7 MMTCE. CO2 from fossil fuel combustion, which is the largest source of U.S. greenhouse gas emissions, accounted for 80 percent of weighted emissions in 1998. Emissions from this source grew by 11 percent (148.1 MMTCE) from 1990 to 1998 and were also responsible for over 80 percent of the increase in national emissions during this period.
The most common greenhouse gases are carbon dioxide, methane, nitrogen oxides and ozone depleting substances. In 1998, methane emissions resulted primarily from the decomposition of wastes in landfills, manure and enteric fermentation associated with domestic livestock, natural gas systems, and coal mining. Emissions of N2 O were dominated by agricultural soil management and mobile source fossil fuel combustion.
Particulate matter is another gaseous emission that can be considered a solid waste. Particulate matter is emitted from coal burning power plants, diesel engines, incinerators and the burning of biomass, such as rice straw, wood, bagasse and charcoal. Particulate matter is of concern because very small particles may not be able to be filtered-out by the respiratory system of a mammal.
Municipal Solid Waste
Municipal solid waste (MSW)—more commonly known as trash or garbage—consists of everyday items such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, paint, and batteries. In 1996, U.S. residents, businesses, and institutions produced more than 209 million tons of MSW, which is approximately 4.3 pounds of waste per person per day, up from 2.7 pounds per person per day in 1960. However, the number of landfills in the US dropped from almost 8,000 in 1988 to about 2,314 in 1998.
Twenty-seven percent (27%) of MSW was recovered and recycled or composted, 17 percent was burned at combustion facilities, and the remaining 55 percent was disposed of in landfills. It is projected that by the year 2005 the US will produce almost 240 million tons of MSW, with paper and paperboard to the dominant material.
Although 17% of the MSW was incinerated in 1996, it is highly unlikely that incineration will be the choice of technologies for alleviating landfill disposal. For example, in November 2000 the U.S. EPA released its final ruling regarding incineration of medical waste. It is believed that due to the new regulations regarding the formation and subsequent release of dioxins from medical waste incinerators, more than 80% of the medical waste incinerators will be decommissioned within the U.S. Likewise, since MSW contains precursor chlorine molecules regulations regarding incineration emissions from landfills may follow in step with medical waste incinerator emission regulations.
It is evident that an urgent need exists to eliminate or reduce the amount of MSW disposed of in landfills in addition to reclaiming the waste within the landfill. Also, many industrial and municipality wastewater treatment plants will dispose sludge in landfills for a nominal charge more commonly referred to as a “tipping fee.” It would be extremely beneficial to both society and to industrial plants or municipalities if this sludge could be recovered onsite as energy in lieu of transporting it to a landfill for final deposition into the ground. A technology that would allow a plant to achieve substantially zero discharge of solid wastes would be highly beneficial.
Oil and Gas Well Drill Cuttings
Another industry, which can benefit from a process or apparatus which could achieve substantially zero discharge for wastes is the oil and gas industry. When an oil or gas well is drilled, the material that is left over from the “hole in the ground” is referred to as drill cuttings. Typically, for every foot drilled about 1.2 barrels of drill cuttings are produced per well. The disposal of the separated shale and cuttings is a complex environmental problem. Drill cuttings contain not only the mud product that can contaminate the environment, but it also typically contains oil that is particularly hazardous to the environment, especially when drilling in a marine environment.
For example, in the Gulf of Mexico, there are hundreds of drilling platforms that drill for oil and gas by drilling into the sub-sea floor. These drilling platforms can be in many hundreds of feet of water. In such a marine environment, the water is typically crystal clear and filled with marine life that cannot tolerate the disposal of drill cuttings. Therefore, there is a need for a simple, yet workable solution to the problem of disposing of oil and gas well cuttings in an offshore marine environment, as well as in other fragile environments where oil and gas well drilling occurs.
Traditional methods of cuttings disposal from an offshore rig usually involves the following procedures and associated costs:    1. Drill cuttings are conveyed from shale shaker to cutting boxes (cutting box rental)    2. Drill cuttings are conveyed to supply boat tank and transported to dock facility(supply boat used to transfer cuttings to dock)    3. The dockside cleaning of tanks—drill cuttings are removed from tanks by emulsifying with water or via bucket brigade (tank cleaning crew=$165/hour)    4. The drill cuttings and water are transferred to an injection well facility    5. Use of an injection well facility—injection of cuttings down-hole for final disposal ($8/barrel).
Thus, drill cuttings disposal cost has been estimated to be between $20 and $30 per barrel.
Unburned Carbon on Fly Ash and Coal Fines
Another solid waste produced in very large tonnages can be found in the coal industry. Coal burning power plants that have low NOx burners produce a fly ash that has a relatively high loss on ignition (LOI) carbon content. Fly ash having an unburned carbon content greater than about 6% usually cannot be used as a cement additive. In addition, washing coal produces coal fines that are traditionally disposed of in a pond. A simple one-step process that can treat flyash and coal fines, or gasify coal without any pretreatment such as washing and grinding would help eliminate many problems associated with coal burning power plants.
The U.S. Department of Energy's National Energy Technology Lab (NETL) has estimated that as much as 2 to 3 billion tons of coal fines lie in waste impoundments at mines and washing plants around the country. Each year, another 30 million tons of coal mined in the United States is discarded into these waste ponds.
Olefin Plants, Ethylene and Propylene
Unburned or unreacted carbon has plagued several other industries and/or processes, such as olefin plants in the petrochemical industry. Olefin plants usually have two main sections; a pyrolysis or cracking section, and a purification or distillation section. In the production of ethylene, ethane is cracked in the presence of steam to produce an ethylene rich feedstock that can then be fed to an ethylene oxide plant. A hydrogen end user, such as a refinery or cyclohexane plant is typically located near an olefins plant. Normally, these plants are integrated into a complex petrochemical facility.
The petrochemical industry, as well as the refining industry, has been plagued with Volatile Organic Carbon (VOC) emission releases, as well as solid waste release problems. Owing to the global warming issue, solutions are being sought for mitigating point source carbon dioxide releases.
A technology that could remove, or decompose of, ethylene oxide in a carbon dioxide stream would be highly desirable to the olefins industry. Likewise, a simple one step reactor and method that could utilize CO2 to treat solid wastes, or other releases in an olefin plant or refinery, would be highly desirable. For example, a simple, cost efficient and highly reliable process that could utilize contaminated CO2 emissions produced from a process, such as in the production of ethylene oxide (EO), in combination with eliminating flares from the same plant, would also be extremely and desirable.
Flares
Flares are common in many petrochemical plants, refineries, oil and gas wells and production facilities, and small commercial chemical plants. Typically, a flare is employed in order to vent a material such as VOCs during plant upsets. For example, an ethylene oxide plant may send its feedstock stream, or a portion thereof, to a flare during temporary shutdowns or plant upsets. A flare is a gaseous waste source and is also a point source emission that is strictly regulated by the US EPA, as well as state and local environmental agencies.
In lieu of plant upsets or shutdowns, flares can be used for the burning of low quality gas that does not meet pipeline specifications. One such low quality gas is biogas that is produced from landfills and which is usually flared or vented. Biogas is typically comprised of methane and CO2, as well as trace amounts of water, sulfur compounds and chlorinated compounds. A valuable resource is being wasted by flaring such a gas with the end product being carbon dioxide—a green house gas—with the potential for releasing toxic emissions. A process that could eliminate flares, provide substantially zero discharge and produce a valuable chemical feedstock would be highly beneficial.
The US, as well as the rest of the world, are in need of a simple solution, such as that provided by the instant invention, for eliminating waste releases. Likewise, due to the rising costs of oil and gas, in addition to aging refineries and petrochemical plants coupled with a population increase, there exists an immediate need for the production of cleaner fuels and/or processes that do not require world-class size refineries and plants.
A relatively small, portable, modular and efficient industrial chemical reactor with a high through-put and yield would be desirable to the aforementioned applications and industries. Likewise, a small residential chemical reactor that could treat household garbage or yard trimmings onsite would dramatically reduce disposal of solid wastes into landfills. An example of the top four materials generated from households for 2000 and projected for 2005 respectively, are: